Sand-blast apparatus



June 8 1926.

C. A. WICKSTROM ET AL SAND BLAST APPARATUS Filed Oct. 15, 1920 8 s s. 3 H g JizVenTors W/[sifvm limes STPaZP' Patented June 8, 1926.

Uhll'l 51E STATES PATENT OFHQE.

onnnnns A. wroxsrnon nun JAMES s. PATEY, or cnroaao, rLLrnoIs, AssIenon-s 'ro wnsrnnn ELECTRIC COMPANY, rnconronnrnn, or new YORK, n. Y., A son PORATION OF NEVT YORK.

SAND-BLAST AEPABATUS.

Application filed. October 15, 1920.

This invention relates to sand blast apparatus, and more particularly to means for automatically maintaining; a uniform level of sand in the supply chamber.

The object of this invention is to provide means whereby a continuous uniform quantity of sand will be supplied to the sand blast nozzle, thereby resulting in uniform operation of the machine.

Another object is to improve the operating conditions so it will not be necessary for the operator to supply sand to the sand supply chamber, but merely to reload the sand hopper at long intervals, which will r depend upon the size of the hopper.

in its preferred form this invention consists of a sand hopper associated with a sand supply chamber in such relation that the level of the sand in the chamber is maintained at a constant height which is best adapted to permit it to be furnished to the blast in the quantity desired and at a uniform rate.

In the specific form of this invention illustrated the sand supply chamber is located below a sand hopper which is connected therewith by a chute through which the sand is fed by gravity from the hopper to the supply chamber.

In the drawings:

Fig. 1 is a front elevation of a sand blast apparatus equipped with the improved means for feeding sand to the sand supply chamber partly broken away, and

Fig. 2 is a schematic View thereof partly in section.

As shown in the drawings, 10 represents a bench or table for supporting the apparatus. A sand blast nozzle 11 and the operuting space are enclosed by a cabinet 12 to, confine the dust therein, which is drawn off by a suitable exhaust 13 positioned in the upper portion of the cabinet. Located below the cabinet 12 is a sand supply fixture 15 provided with a chamber 16 and connected with the operating chamber by a chute 17 which carries the spent sand after being blasted from the nozzle 11 back to the sand supply chamber 16. An air agitator nozzle 18 is located within the chamber 16 which tends to keep the sand therein in a suitable condition to be drawn and also to facilitate the drawing of the sand therefrom.

Serial No. 417,252.

The sand blast nozzle 11 is secured to a chambered fixture 19 which carries therein an air nozzle 20 which extends a Short distance into the sand blast nozzle 11 to give the correct siphoning elfect. The sand supapproximately 15 and through which the sand is drawn therefrom to the sand blast nozzle 11. An air supplyline 22 of a suitable size is connected with the air nozzle 20 at the top of fixture 19 and with the air agitator nozzle 18 at the bottom of the sand supply fixture 15. A main valve 24 for controlling both nozzles is provided and an auxiliary valve is placed in the line to the air nozzle so that the air thereto can be reduced without reducing the pressure to the air agitator nozzle 18.

Located'on the bench 10 and to one side of the cabinet 12 is a hopper 28 for the storing of sand. The bottom of the hopper 28 is open and is connected with the sand supply chamber 16 near its top portion and opposite the point of connection therewith of the pipe 21 by a chute 29 disposed at an angle of approximately The chute 1? is connected with the sand supply chamber 16 at a point midway between and on a line with the chute 29 and the pipe 21. The sand flows from the hopper 28 by gravity and the angular relation of the entrance of the chute 29 and the pipe 21 with the chamber 16 results in the sand always tending to form a constant level therein during the operation of the apparatus, denoted by dotted line80. The sand being drawn from the supply chamber 16 through the pipe 21 to the sand blast nozzle 11 by the action of the air nozzle 20 which is supplied with a uniform pressure of air, it is essential that a constant and correct amount of sand be at all times in the supply chamber 16 to give a uniform treatmentto the objects operated upon. Due to the constant agitation of the sand in the chamber 16 by the nozzle 18, the withdrawal of sand. therefrom by the siphoning effect of the air flowing through the nozzle 20 and the return of the spent sand thereto, the sand in the chamber 16 is not maintained at a sharply defined level during the operation of the apparatus. However, when the apparatus ceases to operate the sand settles and the spent sand returning through the chute l7 joining the sand supply through the chute 29 at the angle shown, tends to retard the flow through the latter mentioned chutes proportionately and thus the level 30 is reestablished. Because of this tendency o1 the sand in the vchamber 16 to return to the level 30 and to thus compensate for the difference in the, volume of sand withdrawn through the pipe 21 and that returned through-the chute 17, th'e sup" ply of sand in the chamber 16 is maintained substantially constant during the operation of the machine. It the pressure in the air supply line 22 is varied, the flow from the chute 29 will be more or less, but a constant level will still be maintained.

Due to the angular relation of the points of attachment to the chamber 16 of the chutes l7 and 29 and the pipe 21, irs well as due to the resultant tendency of the sand in the chamber to return to the level 30, air may freely pass at all times from the nozzle 11 through the chute l7 and the chamber 16 to the pipe 2l thereby assisting in the withdrawal of sand from the chamber 16.

The sand level 30 beneath the chute 17 and within the supply chamber 16 provides for a circulation of air from the chambered fixture 19 through the chute 17, supply chamber 16, pipe 21, and back to the fixture 19, thereby facilitating the drawing of sand from the supply chamber 16.

Suitable hand holes 31 equipped with split rubber sleeves 32 to keep the dust confined within the cabinet are provided in the front wall of the cabinet 12 for the entrance of the objects to be operated upon. A glass window 83 is also located in the front wall of the cabinet and in line with the sandblast nozzle 11 to enable the operator to position the objects to be operated upon.

What is claimed is:

1. In a sandblast apparatus, a cabinet, an exhaust duct connected therewith for with drawing pulverized sand from said cabinet, a blasting nozzle within said cabinet, a sand supply chamber collecting spent sand from said blasting nozzle, a sand storage hopper connected with said chamber for furnishing an amount of said thereto approximately equal to the pulverized sand withdrawn through said exhaust duct, a conduit coni'iecting the chamber with the nozzle, said sand storage hopper and its connection with the supply chamber being so designed that the level of sand within the chamber is maintained substantially constant, an agitator nozzle in the supply chamber and below the level of sand therein, and means for supplying a current of air to the blastingnozzle and to the agitator nozzle for moving sand from the supply chamber through the conduit to the blasting nozzle.

2. In a sand blast apparatus, a sand blast nozzle, a sand supply chamber, a sand storage chamber connected therewith for supplying a stream of sand thereto, means for moving sand from the supply chamber to the nozzle and means connected to the supply chamber tor guiding spent sand from the nozzle. against the stream of sand flow-- ing into the supply chamber fromthe storage chamber to assist in maintaining asubstantially constant amount of sand in the supply chamber.

In a sand blast apparatus, a sand blast nozzle, a sand supply chamber, a first conduit attached to the chamber for supplying sand to the nozzle, means for moving the sand from the chamber through the conduit and the nozzle, a sand reservoir, a second conduit attached to the chamber for supplying sand thereto from the reservoir, and a third conduit attached to the chamber between the first and second conduits and ex tending at an angle of approximately 45" from each of said first and second conduits for directing the sand expelled from the nozzle against the sand flowing from the second conduits to thereby restrict the amount of sand supplied to the chamber from the reservoir to the difference between the amounts supplied to and returned from the nozzle.

In witness whereof, we hereunto subscribe our names this 29th day of Sept, A. 1).,

CHARLES A. WICKSTROM. JAMES S. PATEY.

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